JPS5857478A - Water ink - Google Patents

Abstract

PURPOSE:To provide water ink which scarcely causes bronzing even in the form of dye ink having an increased concentration and gives handwriting having a good density, consisting of a water-soluble dye, a water-soluble org. solvent, water and oxalic acid and/or an oxalate salt. CONSTITUTION:Water ink consists of a water-soluble dye such as C.I. Direct Black, a water-soluble org. solvent such as ethanol, water and oxalic acid and/ or an oxalate salt such as sodium oxalate. As compared with dye ink, pigment ink gives handwriting having a good density and hence is used as drawing ink, designing ink, etc. However, pigment is liable to agglomerate with time, so that it is necessary to disassemble writing utensils and to wash them. When the concn. of dye ink is increased, bronzing is liable to occur whereby handwriting reflects light and emits yellow to red light, and as a result there is a difficulty in reading it. By adding oxalic acid or an oxalate salt, the bronzing can be prevented and the necessity of disassembling and washing the writing utensils can be eliminated unlike the use of pigment ink.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water-based ink, and more particularly to a daffodil ink that provides good handwriting density.

Conventionally, pigment inks have been used as inks for drafting, design, etc. because they provide a better handwriting density than dye inks.

The zeta pigment tends to aggregate over time. For example, when the pigment ink was used in a small-tube type writing instrument for drafting, it was necessary to disassemble the writing instrument and use it six times.

It is possible to approach the handwriting density of pigment ink by lowering the dye # degree in dye ink by 1σ, which has fewer problems such as # year, but as the handwriting dries, black handwriting in particular becomes lighter with this ink. There is a problem in that a so-called bronzing phenomenon occurs, in which the handwriting appears to glow yellow or red due to the reflection of light, and the handwriting no longer appears dark, and this phenomenon is particularly noticeable on trace song paper used for drafting.

Therefore, the inventor of the present invention completed the present invention after various studies in order to develop a water-based ink that is less prone to bronzing even with dye inks with increased # strength and can provide good handwriting # strength. Something.

That is, the gist of the present invention is a water-based ink comprising at least a water-soluble dye, a water-soluble organic solvent, water, and oxalic acid and/or a salt thereof.

Although the details of the effects of oxalic acid and/or d/8-oxalate are unknown, they are probably based on the following principle. That is, oxalic acid in the ink combines with the alkaline component in the ink, and like oxalate,
It exists stably in a dissolved state in ink, but when written.

The solubility of oxalate in the ink is low.

As the handwriting dries, it precipitates as microcrystals.

Since the handwritten surface becomes rough and reflects light diffusely, the bronzing phenomenon can be suppressed, and it is thought that good handwritten density can be obtained.

Next, the composition of the present invention will be explained.

As water-soluble dyes, direct dyes and acid dyes can be used.
Direct dyes include U, 1. Direct black 19.
Same 22. 38. G.1. Direct erotic 4. Same 27
, C,1, Direct Orange 8, i4. U,
T, Direct Red 1. Same 4゜ Same 23, 0.1. Direct Blue 1. Same 6. Acidic dyes such as 86, C1, Acid Plaque 2. Same 24. 26. Same 52.
U, 1. Assisted Yellow 9. Same 17. Same 23. C,1,
Acid orange 19. 20. O, 1, Ants Doresod 7° 17, Same 15. U, 1. Acid blue 1. Same 9
゜Same 25. Although dyes such as No. 27 can be used alone or in combination, direct dyes are preferable in consideration of the water resistance of handwriting.

The amount of water-soluble dye used is the total amount of water-based ink ((for 5
~20% by weight, and preferably 10 to 20% by weight when high handwriting density is required for drafting, design, etc.

Water-soluble organic solvents are those that are compatible with water and are used as dye solubilizers, such as methanol, ethanol,
Monohydric alcohols such as isopropanol, ethylene glycol, phlopylene glycol, 13-butylene glycol, diethylene glycol, triethylene glycol.

Thiogetanol, methyl cellosolve, ethyl selonlube, butyl selonlube, methyl cellosolve acetate,
Ethyl cellosolve acetate.

Dimethyl cellosolve, diglyme, glycerin.

Methyl calpitol, polyhydric alcohols such as carpitol and their derivatives, formamide, dimethyl sulfo 7
tetrahydrofurfuryl alcohol, diacetone alcohol, 2-pyrrolidone, N-methyl-2-pyrrolidone, 4-butyrolactone, sulfolane, monoethanolamine, jetanolamine, triethanolamine,
Ethylene carbonate, propylene carbonate, acetonitrile, morpholine and the like can be selected and used as appropriate, and the amount used is preferably 1 to 40% by weight based on the total amount of the water-based ink.

Also, use of water as the main solvent 4. The total amount is preferably 40 to 95% by weight based on the total amount of the water-based ink.

Furthermore, oxalic acid and/or its salt, which is a feature of the present invention,
It is used to suppress the bronzing phenomenon, and the amount used is 01 to 1.5% by weight based on the total amount of water-based ink.
@: c'o3 to 1.0 weight ratio is preferable. At 0.01% by weight, the effect of its addition is small (at 1.5% by weight or more,
Because the solubility of oxalic acid and/or salt is not good,
There is a risk of impairing the stability of the ink over time.

In addition to the above-mentioned components, in order to adjust the viscosity of the ink appropriately and improve the abrasion resistance of handwriting, water-soluble Hatake molecules are added to the total amount of the ink to 5% by weight. When you want to add this effect to make ink flow more smoothly while writing.

Penetrants such as various anionic and/or nonionic surfactants are contained within 3% by weight based on the total amount of ink, and formalin, phenol, and pentachloro are used to prevent ink flow inhibition due to mold growth and ink decay. Sodium phenol.

A small amount of antiseptic and fungicidal agent such as sodium dehydroacetate may be added as appropriate, and when the ink comes into contact with metal parts, anticorrosion agents such as benzotriazole and ethylenediaminetetraacetate may be added as necessary to prevent metal corrosion. A rust preventive agent may also be added as appropriate. In addition, in some cases, urea, ethylene urea, etc. may be added to increase the dissolution stability of the dye and suppress ink drying at the pen tip, and to control the drying time of the ink at the handwriting and the pen tip. There is no problem in adding sorbitol, polyethylene rangelicol, etc.

The ink can be produced by a simple operation of appropriately selecting the above-mentioned ink components according to the required characteristics of the ink, mixing and dissolving them, but the ink can be produced more easily by moderate IJII heat and 2 stirrings.

The present invention will be explained below with reference to Examples.

In the examples, "part" means 1 part by weight.

Example 1. (Black ink using acid dye) Eisen Opal Black W11 11.0 parts (manufactured by Hodogaya Chemical, CL Acid Black 52) Water Red ÷ 2 0.3 parts (manufactured by Orient Chemical,
C, 1, Acid Red 87) Water Yellow ÷ 1
0.3 parts (manufactured by Orient Chemical ■, c,
■, Acid Yellow 25) Kuraray Bobal 117 (10
% aqueous solution) 50 parts (Polyvinyl alcohol manufactured by Kuraray) Emulgen 147 0.1 part (manufactured by Kao Atlas ■, nonionic surfactant) Bentachlorophenol sodium (10% aqueous solution) 01 part Sodium hydroxide 01 part ethylene glycol 100 parts ethanol
05 parts sodium oxalate 07 parts water
71.9 parts The mixture of the above components was stirred at 30 to 40°C for 2 hours and then filtered to obtain a black ink with a viscosity W of 3.8 cP (at 25°C). When this ink was filled into a commercially available small-tube drafting pen and written on tracing paper, the ink flowed out smoothly and clear handwriting with high contact was obtained.

However, when writing on tracing paper with an ink that does not contain sodium oxalate, the handwriting was black with a high degree of ('φ) immediately after writing, but as the handwriting dried (Vζ) A bronzing effect appeared and the handwriting became blurred and difficult to see.

Example 2 (Black ink using direct dye) Kayaku Direct Deep Blank EX 10.0 parts (manufactured by Nippon Kayaku@,
U, T, Direct Black 38) Kayaku Direct Orange R0, 2 parts (manufactured by Nippon Kayaku ■, C3, T, Direct Orange 8)
) Mitsui Nylon 7 Asto Blue 0.3 part (
Manufactured by Mitsui Toatsu Chemical ■, U, 1. Anonodo Blue 25)
Polyvinylpyrrolidone K 30 0.7 parts Pentakuoo Sodium phenol (10% aqueous solution) [
1.7 parts Sodium hydroxide 0
2 parts Ethylene glycol 10.0 parts Methyl cellosolve 05 parts Thiogetanol 5 parts Sorbitol o5 parts Sodium oxalate 05 parts Water
72.0 parts Each of the above components was treated in the same manner as in Example 1 to obtain a viscosity of 3.7 cP.
(a+25°C) black ink was obtained.

When this ink was used to write on tracing paper in the same manner as in Example 1, the ink flowed out smoothly and clear handwriting with high density was obtained.

However, when writing on tracing paper with an ink that does not contain sodium oxalate, a yellowish bronzing phenomenon appears in the dark marks, as in the +frrI example, and the handwriting becomes blurry and difficult to see.

As described above, the ink of the present invention is a water-based ink that is less likely to cause bronzing in handwriting and provides good handwriting density.

2. In the present invention, 1% Vcl for brush AC tools! ! We have explained water-based ink for drawings, but for general writing instruments, stamps, etc.
For printing and inkjet printers.

It can also be applied as a water-based ink for wire dot printers.

Patent applicant: Pentel Co., Ltd.

Claims (1)

[Claims] A water-based ink comprising at least a water-soluble dye, a water-soluble organic solvent, water, and oxalic acid and/or a salt thereof.